We are conducting research in four separate areas: (a) Protein conformation: the preferential hydration of proteins is being studied as a function of temperature. A correlation between preferential hydration changes and breaks in Arrhenius plots has been discovered. (b) Antibodies: the activation of Clq by a univalent hapten-antigen complex is being studied. The nature of hapten-antibody complexes formed with tri- and tetravalent haptens is being investigated. (c) The rotor speed effect of the sedimentation behavior of high molecular weight DNA is being studied. (d) The interaction between histone IV and DNA is being investigated by ultracentrifugation and electron microscopy. Cooperative binding of histones to DNA does not seem to occur if the histones are phosphorylated.